1. Field of the Invention
The present invention relates in general to data processing and in particular, to digital decoding circuitry and methods and systems using the same.
2. Description of the Related Art
The ability to process digitized audio information has become increasingly important in both the home theater and personal computer (PC) environments. In the home theater environment, high quality sound which fills the room is a key advantage of digital audio. Digital receivers, compact disc players, laser disc players, VCRs and televisions are a few of the sucessful applications of the digital audio technology. This technology continues to progress, and as it does, its applications are becoming increasingly sophisticated as improvements in sound quality and sound effects are sought.
A similar situation is true in the PC environment. Among other things, digital audio is a significant element of many PC-based multimedia audio applications, such as gaming and telecommunications. Audio functionality is therefore typically available on most conventional PCs, either in the form of an add-on audio board or as a standard feature provided on the motherboard itself. In fact, PC users increasingly expect not only audio functionality but high quality sound capability from their system.
One of the key components in many digital audio information processing systems is the decoder. Generally, the decoder receives digital data in a compressed form and converts that data into a decompressed digital form. The decompressed digital data is then passed on for further processing, such as filtering, expansion or mixing, conversion into analog form, and eventually conversion into audible tones. In other words the decoder provides the proper hardware and software interfaces to process the possible compressed (and decompressed) data sources, to feed the destination digital and/or analog audio devices. In addition, the decoder must have the proper interfaces required for overall control and debugging by a host microprocessor or microcontroller.
Since, there are a number of different audio compression/decompression schemes such as Dolby AC3 and DTS, and interface definitions, such as S/PDIF (Sony/Phillips Digital Interface), a state of the art digital audio decoder should be capable of supporting multiple compression/decompression formats. Such a decoder should also perform additional functions appropriate to the decoder subsystem of a digital audio system, such as the mixing of various received digital and/or audio data streams. Notwithstanding these issues, it is essential that such a decoder handle the data throughput transparently with efficiency, speed and robustness. Thus, the need has arisen for an digital audio decoder which provides maximum utility and flexibility in view of the array of different formats and interfaces.